President Bush is ready to make a fresh call on Iraq to admit weapons inspectors while his strategists consider setting a deadline with serious consequences if the appeal is rejected, even as old allies withhold support.

The implicit warning of U.S. military action to oust Iraqi President Saddam Hussein would be in a U.N. Security Council resolution by Britain that would have to avert a veto by Russia, China or France to pass.

The president will make his case against Iraq at the United Nations on Thursday, urging the nations of the world to compel Saddam to admit weapons inspectors and to disarm.

A senior U.S. official said he is "going to make clear that the current regime in Iraq is an outlaw regime, that it has defied U.N. resolutions for 11 years now."

Trying to spur the United Nations to action, Bush intends to tell the 190 nations that Saddam's "outlaw regime" is challenging the world organization with its defiance of a string of resolutions, the official said.

Condoleezza Rice, Bush's national security adviser, put the case graphically on Sunday. With Iraq building up an arsenal of nuclear and other destructive weapons "we don't want the smoking gun to be a mushroom cloud."

Bush contends he does not need new legal authority to use force to overthrow Saddam. The White House cites U.N. resolutions dating from 1990-91 Persian Gulf war that reversed Iraq's annexation of Kuwait.

But with German Chancellor Gerhard Schroeder dismissing action against Iraq as an "adventure," and only Britain solidly in the U.S. camp, Bush's policy could stand a boost even though the president is prepared to act unilaterally, if need be.

Israeli foreign minister Shimon Peres said Bush had told him he would do what he must, even if alone. Peres said he told Bush: "Mr. President, if you act you won't be alone."

"Everyone at heart understands that this is a brutal man, who will be a danger to the whole world if he has nuclear, chemical or biological weapons in his hands," Peres said.

British Defense Secretary Geoff Hoon said in dealing with Iraq, diplomacy should and will come first. Hoon met with Defense Secretary Donald H. Rumsfeld at the Pentagon Wednesday.

"But when dealing with dictators, diplomacy must be backed up by the certain knowledge in the dictator's mind that behind the diplomacy lies the real threat of force being used," he said in a speech at the Heritage Foundation in Washington.

"So our message to Saddam is plain: no more conditions, no more games, no more prevaricating, no more undermining the U.N.'s authority."

He said Saddam was in breach of at least 23 U.N. obligations and was doing all he could to acquire weapons of mass destruction.

Bush administration officials are trying to muster support for military action against Iraq in Congress with mixed results.

Sen. Joseph Biden, D-Del., in a speech to the Philadelphia World Affairs Council, said he did not think time had run out for diplomacy.

Biden, chairman of the Senate Foreign Affairs Committee, said worst option would be for the United States to move against Iraq alone.

Several prominent House Democrats questioned whether the White House's urgency to oust Saddam was politically motivated at a time when the midterm elections in November likely will determine control of Congress.

"I don't like to say this is a political issue, that he's trying to distract the public from what's going on (domestically), because it's so serious that I hope it isn't," said Rep. John P. Murtha, D-Pa., the ranking member of the House Appropriations Defense subcommittee.

Rep. Nick Rahall, D-W.Va., planned to depart for Iraq on Wednesday to inquire about the possibility of U.S. negotiations with that country to head off American military action.

Rahall said that he supported the intervention of the American-led coalition that liberated Kuwait from Iraqi control 11 years ago. But this time, he said, "I have a lot of unanswered questions."

And Sen. Hillary Clinton, D-N.Y., was skeptical of using force.

"Obviously, we all support a regime change," she said on Fox-TV. "The question is how do we get it done, at what cost. And by costs I'm not talking financially -- I'm talking about unintended consequences, lives, people being thrown into turmoil in other parts of the world." Any plan to oust Saddam must not require the United States to act alone, many lawmakers say.

Under the agreement that ended the Gulf war and several U.N. Security Council resolutions, Iraq is forbidden to develop weapons of mass destruction and under orders to allow any already in its arsenal to be destroyed.

"I believe this is an international problem, and that we must work together to deal with the problem," Bush said during an appearance Tuesday at the Afghan Embassy.

Bush linked his goal of toppling Saddam to the war on terror he began after the Sept. 11 attacks a year ago.

"I'm deeply concerned about a leader who has ignored the United Nations for all these years, refused to conform to resolution after resolution after resolution, who has weapons of mass destruction," Bush said.